1. Field of the Invention
This invention relates generally to a thin film electroluminescent edge emitter structure, and more particularly, to linearly-arrayed light-emitting pixels of the thin film edge emitter structure incorporating an optical lens system and a multi-color light emission system.
2. Description of the Prior Art
It is well known that an electroluminescent device may be utilized to provide an electronically controlled, high resolution light source. One arrangement which utilizes an electroluminescent device to provide such light source is a flat panel display system, such as disclosed in U.S. Pat. No. (4,110,664) to Asars et al and Luo et al U.s. Pat. No. (4,006,383) which are assigned to the assignee of the present invention. However, in a flat panel display system, light emissions providing the light source are normal to the face of the electroluminescent device and must pass through one of the electrodes. Thus, the thickness of the electroluminescent device and the transmissiveness of the electrode are practical limitations on the brightness of the light emissions which can be attained by the flat panel display system.
Another arrangement utilizing an electroluminescent device to provide such light source is a thin film line array, or edge, emitter, such as disclosed in a U.S. Pat. No. (4,535,341) to Kun et al which is also assigned to the assignee of the present invention. The brightness of the light emissions attained by the thin film electroluminescent edge emitter structure of the Kun et al patent is not subject to the same limitations as the flat panel display system due to the fact that it provides light emissions at the edge of the electroluminescent device. Edge emission come from a depth of the electroluminescent device corresponding to its length, and not to its thickness, and does not pass through one of the electrodes. For reference herein, the length of an electroluminescent device is the distance between its light emitting edge and its opposite nonlight emitting edge. Thus, edge emissions of the thin film line array, or edge, emitter light source are typically 30 to 40 times brighter than the face emissions of the flat panel display light source under approximately the same excitation conditions.
From the above discussion, it can be appreciated that the thin film edge emitter structure of the Kun et al patent potentially provides a high resolution light source promising orders of magnitude of improved performance over the flat panel face emitter structure in terms of light emission brightness. However, many areas of thin film edge emitter structure design are still in need of further improvements to enhance performance overall. Two such areas are the pattern and levels of light energy projected by the edge emitter structure.